Pertuzumab plus trastuzumab (P+T) in patients (Pts) with colorectal cancer (CRC) with ERBB2 amplification or overexpression: Results from the TAPUR Study.

Abstract

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Background: TAPUR is a phase II basket trial evaluating anti-tumor activity of commercially available targeted agents in pts with advanced cancers with genomic alterations. Results in a cohort of CRC pts with ERBB2 overexpression or amplification treated with P+T are reported. Methods: Eligible pts had advanced CRC, no standard treatment (tx) options, measurable disease, ECOG PS 0-2, and adequate organ function. Genomic testing was performed in CLIA-certified, CAP-accredited site selected labs. Pts had ERBB2 overexpression or amplification, or certain ERBB2 mutations. Recommended dosing after initial dosing was P, 420 mg IV over 30-60 mins every 3 weeks (wks) and T, 6 mg/kg over 30-60 mins every 3 wks. Simon two-stage design was used to test a null rate of 15% vs. 35% (power = 0.85; α = 0.10). If ≥2 of 10 pts in stage 1 have disease control (DC) (objective response (OR) or stable disease at 16+ wks per RECIST (SD16+)), 18 more pts enrolled. If ≥7 of 28 pts have DC, the tx is worthy of further study. Secondary endpoints are progression-free survival (PFS), overall survival (OS) and safety. Results: Twenty-eight pts enrolled from November 2016 to September 2018 were evaluable for efficacy and safety. Demographics and outcomes are summarized in Table. All pts had ERBB2 amplification; 1 also had an ERBB2 mutation. 79% of pts had at least 3 prior txs. Four PR and 10 SD16+ were observed for DC and OR rates of 50% (90% CI, 36% to 60%) and 14% (95% CI, 4% to 33%), respectively. Two pts had at least one grade 3 AE or SAE at least possibly related to P+T including anemia, infusion reaction, and left ventricular dysfunction. Conclusions: The combination of P+T showed anti-tumor activity in heavily pre-treated CRC pts with ERBB2 amplification . Additional analyses by RAS mutation status are pending. Further study is warranted to confirm efficacy of P+T in this population. Clinical trial information: NCT02693535.

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